The lunar cycle: effects of full moon on renal colic

To evaluate renal colic frequency in different seasons and around full moon. A total of 1481 patients with renal colic were studied retrospectively addressing days of a month both in solar and lunar calendar. The mean age of the patients was 57 ± 13 years. Total admissions in summer was 613; of which 288 (41%), 199 (39%), and 126 (43%) were in years 2002, 2003, and 2004, respectively. The highest frequencies in solar calendar were on days 2 (56), 20 (63), and 27 (59) and the lowest were on days 6 (36), 22 (38), 26 (34), and 31 (31). We did not find any statistically significant association according to solar calendar (P = .3). In lunar calendar, most of the admissions were on day 15 (69) and the lowest rates were on days 1 (25) and 30 (26), which was statistically significant (P = .04). Renal colic frequency is not correlated with solar calendar, but its highest frequency in lunar calendar is in the middle of the month period. Although we found a correlation between full moon effect and renal tide, but this is a new window for further studies.